1. Field of the Invention
The present invention relates to a recording tape cartridge accommodating, within a case, a single reel on which is wound a recording tape, such as a magnetic tape or the like, which is used as a recording/reproducing medium mainly for computers or the like.
2. Description of the Related Art
Conventionally, recording tape cartridges have been known in which a recording tape, such as a magnetic tape or the like, which is used as a data recording/reproducing medium for computers or the like, is wound on a single reel, and the reel is rotatably accommodated within a case. The case of this recording tape cartridge is formed substantially in the shape of a rectangular box by an upper case and a lower case, which are substantially tray-shaped, being joined together in a state in which the peripheral walls thereof abut one another.
In this recording tape cartridge, a leader member, such as a leader tape, a leader pin, a leader block, or the like, is fixed to an end portion of the recording tape. Due to a pull-out member of a drive device pulling the leader member out, the recording tape is pulled-out from the interior of the case. The pull-out member is often provided at the side portion of a loading opening into which the recording tape cartridge is loaded. Therefore, the opening of the recording tape cartridge for the pulling-out of the leader member (the recording tape) is often formed at the corner portion of the case.
When the leader member is a leader tape or a leader pin, a door which opens and closes the opening is provided. Namely, in the case of a leader tape, the opening is opened and closed by, for example, a door which is supported so as to be able to rotate around a supporting shaft provided at a front wall side (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2000-11591). In the case of a leader pin, the opening is opened and closed by, for example, a door which is slidably supported at a side wall side.
When the leader member is a leader tape, there are cases in which the leader tape is disposed along the side wall of the case. In such a case, because the pull-out member of the drive device engages (grasps) the leader tape from the side wall side, the opening for the pulling-out of the leader tape (the recording tape) is formed from a corner portion of the case and along the side wall.
However, if the leader tape is disposed toward the rear of the case, because the length of the opening formed in the side wall extends toward the rear, a problem arises in that the length of the door becomes that much longer. Namely, when the door rotates in order to open the opening, the problem arises that the door interferes with the pull-out member or the like of the drive device, and, as a result, is unable to open. Accordingly, it is preferable to dispose the leader tape toward the front such that the distal end surface thereof is as close as possible to the corner portion.
However, when the leader tape is disposed toward the front, a problem arises in that the leader tape interferes with (contacts) the door. Namely, jutting portions, which are formed in a vicinity of the distal end of the leader tape, are held by being accommodated (inserted) in accommodating recesses formed in the upper case and the lower case. However, at the time when the door closes the opening, if the distal end surface of the leader tape is held at a position at which it interferes with (contacts) the door, because the leader tape is more rigid than the recording tape (the magnetic tape), the jutting portions transmit force to the longitudinal direction rear side of the recording tape and press against the closed rear wall surfaces of the accommodating recesses. A problem arises in that the distal end portion of the leader tape is nipped between the door and the accommodating recesses and deforms.
Thus, as shown in FIG. 6, an allowing portion 54, which is concave in a plan sectional view and which allows avoidance of contact between a distal end surface 52C of a leader tape 52 and a door 50 when the opening is closed, is formed at the inner surface of the door 50. Namely, by forming such an allowing portion 54, when the opening is closed, a clearance C2 of about 0.2 mm is ensured between the distal end surface 52C of the leader tape 52 and the inner surface of the door 50 (i.e., the allowing portion 54), and interference (contact) between the leader tape 52 and the door 50 is avoided.
However, when the opening is closed, the front-back direction joggling of the door 50 with respect to the case is about 0.2 mm. Accordingly, even if this clearance C2 is ensured, if impact is applied to the door 50 due to dropping or the like, there is the concern that the distal end surface 52C of the leader tape 52 will interfere with (contact) the inner surface of the door 50 (the allowing portion 54).
The allowing portion 54 cannot be made any deeper because a deeper allowing portion 54 would lower the rigidity of the door 50. Namely, the plate thickness of the door 50 is set to be constant, so that the door 50 does not project out from the case in plan view at the time when the door 50 closes the opening. Thus, by forming the allowing portion 54, a plate thickness D2 of the most thin-walled portion of the door 50 is already less than 0.6 mm. Accordingly, if the allowing portion 54 is formed to be deeper than this, the rigidity of the door 50 cannot be ensured.